The use of vaporized hydrogen peroxide (VHP) is an established antimicrobial process. VHP is widely used to create sterile environments (clean rooms, etc.) and as a component of a contamination control method on sensitive equipment, in animal research labs, healthcare environments and the like. Recent developments have seen VHP considered for use on aircraft after an attack employing biological weapons. However, due to the rigorous requirements placed on aircraft components, there are concerns about the compatibility of the aircraft parts, substrates, adhesives, coatings, etc. with the VHP process. This is especially the case in modern 5th generation aircraft where composite materials are being used to replace many of the more traditional metal components.
The materials used in modern aircraft construction have strict limits on the temperature and other conditions to which they can be exposed. Typically, the aircraft must not be exposed to temperatures greater than 82° C. (180° F.) (the temperature an aircraft stored in direct sunlight at equatorial latitudes might reach).
To address the concern regarding the compatibility of aircraft parts with VHP, alternative methods have been developed to provide biological decontamination without exposing the aircraft to conditions (such as thermal stress) that might compromise the integrity of the materials of the aircraft. As used herein the term “decontamination” refers to the inactivation of bio-contamination, and includes, but is not limited to, sterilization and disinfection. One such method is referred to as Bio Thermal Decontamination (BTD). During a BTD process, an aircraft is heated to a temperature that is at or below the safe storage limit of the aircraft (e.g., about 82° C.) and exposed to high levels of humidity. These conditions have the same effect as steam sterilization and will cause inactivation of biological agents, including bacterial spores. However, because the temperature is low, as compared to a normal steam sterilization cycle (typically autoclaves operate at 120° C. or 130° C.), the time required for effective microbial inactivation is very long (many days).
Thus, there is a need for a decontamination process that provides effective microbial inactivation in a sensible time frame (hours not days) and that is compatible with the materials of modern aircraft.